title: Pro-apoptotic effects of imatinib on PDGF-stimulated pulmonary artery smooth muscle cells from patients with idiopathic pulmonary arterial hypertension.
abstract: BACKGROUND
  Remodeling of the pulmonary artery by an inappropriate increase of pulmonary artery smooth muscle cells (PASMCs) is problematic in the treatment of idiopathic pulmonary arterial hypertension (IPAH). Effective treatment that achieves reverse remodeling is required. The aim of this study was to assess the pro-apoptotic effects of imatinib, a platelet-derived growth factor (PDGF)-receptor tyrosine kinase inhibitor, on PASMCs obtained from patients with IPAH.
  
  
  METHODS
  PASMCs were obtained from 8 patients with IPAH undergoing lung transplantation. Cellular proliferation was assessed by (3)H-thymidine incorporation. Pro-apoptotic effects of imatinib were examined using TUNEL and caspase-3,7 assays and using transmission electron microscopy.
  
  
  RESULTS
  Treatment with imatinib (0.1 to 10 μg/mL) significantly inhibited PDGF-BB (10 ng/mL)-induced proliferation of PASMCs from IPAH patients. Imatinib (1 μg/mL) did not induce apoptosis in quiescent IPAH-PASMCs, but it had a pro-apoptotic effect on IPAH-PASMCs stimulated with PDGF-BB. Imatinib did not induce apoptosis in normal control PASMCs with or without PDGF-BB stimulation. PDGF-BB induced phosphorylation of Akt at 15 min, and Akt phosphorylation was inhibited by imatinib in IPAH-PASMCs. Akt-I-1/2 (1 μmol/L), an Akt inhibitor, in the presence of PDGF-BB significantly increased apoptotic cells compared with the control condition. Thus, Akt-I-1/2 could mimic the effects of imatinib on PASMCs.
  
  
  CONCLUSIONS
  Imatinib has anti-proliferative and pro-apoptotic effects on IPAH-PASMCs stimulated with PDGF. The inhibitory effect of imatinib on Akt phosphorylation induced by PDGF plays an important role in the pro-apoptotic effect.
authors.affiliation: Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan. ichibun@cc.okayama-u.ac.jp
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Nakamura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Akagi
authors.forename: Aiko
authors.initials: A
authors.lastname: Ogawa
authors.forename: Kengo F
authors.initials: KF
authors.lastname: Kusano
authors.forename: Hiromi
authors.initials: H
authors.lastname: Matsubara
authors.forename: Daiji
authors.initials: D
authors.lastname: Miura
authors.forename: Soichiro
authors.initials: S
authors.lastname: Fuke
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Nishii
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nagase
authors.forename: Kunihisa
authors.initials: K
authors.lastname: Kohno
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Morita
authors.forename: Takahiro
authors.initials: T
authors.lastname: Oto
authors.forename: Ryutaro
authors.initials: R
authors.lastname: Yamanaka
authors.forename: Fumio
authors.initials: F
authors.lastname: Otsuka
authors.forename: Aya
authors.initials: A
authors.lastname: Miura
authors.forename: Chikao
authors.initials: C
authors.lastname: Yutani
authors.forename: Tohru
authors.initials: T
authors.lastname: Ohe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ito
mesh_terms: D000293:Adolescent; D000328:Adult; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D000077214:Becaplermin; D001549:Benzamides / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects; D002648:Child; D065627:Familial Primary Pulmonary Hypertension; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000188:drug therapy* / Q000473:pathology; D000068877:Imatinib Mesylate; D008297:Male; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000502:physiology; D010879:Piperazines / Q000494:pharmacology*; D020574:Proto-Oncogene Proteins c-sis / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D011651:Pulmonary Artery / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D011743:Pyrimidines / Q000494:pharmacology*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D001549:Benzamides; D010879:Piperazines; D020574:Proto-Oncogene Proteins c-sis; D011743:Pyrimidines; D000077214:Becaplermin; D000068877:Imatinib Mesylate